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Phase evolution and temperature-dependent behavior of averievite, Cu5O2(VO4)2(CuCl) and yaroshevskite, Cu9O2(VO4)4Cl2статья
- Авторы: Ginga Victoria A., Siidra Oleg I., Firsova Vera A., Charkin Dmitri O., Ugolkov Valery L.
- Журнал: Physics and Chemistry of Minerals
- Том: 49
- Номер: 9
- Год издания: 2022
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- Номер статьи: 38
- DOI: 10.1007/s00269-022-01213-6
- Аннотация: The exhalation copper oxychloride vanadates attract increasing interest in the fields of both physics and chemistry. Based on the results of HT X-ray diffraction study of synthetic analogs of averievite (1) and yaroshevskite (2) and products of their thermal decomposition in air within the temperature range from 25 °C to 800 °C, it was found that 1 is stable up to 500 °C, and 2 is stable up to 480 °C. Both copper oxychloride vanadates expand anisotropically, but exhibit completely different thermal expansion patterns. 1 demonstrates an expansion in the direction perpendicular to the [O2Cu5]6+ layers, but inside the layer, the expansion is isotropic. The thermal expansion of 2 is much more anisotropic. The compression direction α33 is close to the c axis, along which the structure tends to align the chains [O2Cu6]8+ into positions they would occupy in the layers [O2Cu5]6+ of the kagome type which exist in averievite. Meanwhile, the expansion direction α11 is close to the a axis, along which the [O2Cu6]8+ chains shift tending to arrange as fragments of [O2Cu5]6+ layers. The thermal decomposition proceeds with loss of chlorine (most likely, both via hydrolysis/oxidation and evaporation of copper halides) and formation of copper vanadates.
- Добавил в систему: Чаркин Дмитрий Олегович